Course indicator for blind flying and landing



June 7, 1938. F. w. DUNMORE 2,119,530

COURSE INDICATOR FOR BLIND FLYING AND LANDING Filed Nov. 10, 1932 COURSERECEIVING SIT Patented June 7, 1938 2,119,530 COURSE INDICATOR FOR BLINDFLYING AND LANDING Francis W. Dunmore, Washington, D. (3., assignor tothe Government of the United States, represented by the Secretary ofCommerce Application November 10, 1932, Serial No; 642,045

8 Claims. (01. 177-352) (Granted under the act of March 3, 1883, asamended April 30, 1928; 370 0. G. 757) The invention described hereinmay be maning units and I2 are mounted at right angles ufactured andused by or for the United States to each other in a case I3. Drivingunit I! opfor governmental purposes only without the paycrates the 'end'zero pointer I l and driving unit ment of any royalty thereon. l2operates the center zero pointer l5. Such 6 My invention relates to anindicating instrudevices are well known in the art and are ordimentwhich gives both radio beacon course indicanarily provided withyieldable means for returntion and received signal volume indication onthe ing the pointers to their normal positions. These same instrument;or radio beacon course indicapointers both move over face or dial itwhich tion and landing beam path indication on the may have referencelines IT for pointer I d and same instrument, reference ,line l8 forpointer l5. A circle or in- 10 This invention is an improvement on mypredex mark l9 may be placed at the intersections vious inventions inwhich these two indications of lines I! and 48 as an additionalreference point. were given by two separated and distinct in- 20 is asmall electric light. With the instrument struments and is. particularlyuseful in conneccover in place just the face it and pointers it 16' tionwith the system shown in my copending apand are visible to thenavigator. The pointers l5 plication, Ser. No. 627,625. id and i5 aremounted and arranged to move in In this invention two pointer drivingunits are parallel planes, preferably at right angles to mounted in onecase so that the pointers of these each other and to intersect in all oftheir positwo units may be seen on the one instrument tions, the pointof intersection indicating (when 20 face. These units are so arrangedthat the the instrument is operated by both lateral and 20 pointers moveat right angles to each other. The vertical signals) the relative courseand position advantages of this instrument are light weight, of theaircraft with respect to that occupied, less space required andindications given at one when it is following a correct course, which isspot eliminating the necessity for the navigator indicated when saidpointers cross at right angles to glance at several different pointson-his instruor at the index mark I9. 25 ment board. Other uses for andadvantages of Figure 2 represents an application of this my inventionwill be more clearly understood by combined instrument in one form ofcircuit. In reference to the following description and diathis figurethe instrument described in Figure 1, grammatic drawing. is here shownmounted in an annular support it In the drawing:-- cushioned on springs22. The driving coil 34 for 30 Figure 1 is a view of one form of myinvention, a pointer Id of the unit H, is connected to with a face plateforming a portion of its casing the' center terminals of a double-poledoubleremoved to show normally concealed parts. throw switch 24. Aresistance 25 is connected Figure 2 represents this form of my inventionacross the lower terminals of this switch. A reand electric circuitssuitable for use therewith. versing or course selector switch 26 is alsocon- 35 Figure 3 shows the correct position of the two nected acrossresistor 25. 27 and 28 are reed conpointers when an airplane is on acorrect landverter units the inputs of which are connected ing path andbeacon course as indicated in the through conductors 29 to the radiobeacon reaccompanying diagram. ceiving set 31, responsive to the radiobeacon Figure 4 shows approximate positions of my course signalsindicated in Fig. 6. The upper 40 pointers when an airplane equippedwith my interminals of switch 24 are connected to the outvention isabove the correct landing path and to put of the landingbeam receivingset 38 or other the left of thecorrect runway or beacon course type offog landing receiving set through conas indicated in the accompanyingdiagram. ductors 30 responsive to the landing beam 36.

L5 Figure -5 shows approximate positions of my The method and apparatusfor producing the pointers when the airplane is below the correct radiobeacon course and the landing beam are landing path and to the right ofthe desired fully defined in the Bureau of Standards Recourse, asindicated by the accompanying diasearch, vol. 5 of October 1930, Paper#238, Pts. P- III and IV. The driving coil for pointer 23 is o Flgure 618 a dlagrammatic view of a 4-course connected to the center point ofresistor 25 and 5 radio beacon used in conjunction with the landto aterminal of the rectifier in converter 21 and mg beam 36 for givinglateral guidance to port, to the terminal of opposite polarity of therectifier in converter 28. With switch 24 thrown Figure 1 represents oneform of my invention in down in contact with terminals 24 combined in- 5which the two electrical instrument pointer drivstrument 2| serves togive double modulation beacon course indications by means of pointer l5which normally intersects the circle 3| or index 'mark l9 when there isno current in the coils 32 'of a unit l2, and pointer 14 serves'togivesignal volume indication as both conVertersZ'I and 28 cause a RI drop ofthe same polarity across resistor 25. With no current in the drivingcoils of unit II the position of the pointer is as shown at 14,Figure 1. When on the beacon course and with correct received signallevel the two pointers M and I5 intersect at the circle l9.

With switch 24 thrown up in contact with terminals 24 the output of thefog landing receiving set. is connected to the driving coil of unit I1and picks up the beam signal 66. Pointer 33 then serves to giveindications as to the position of the plane with respect to the properlanding path p in the vertical plane while pointer 23 continues to giveindications from the field or runway beacon signal (shown in Fig. 6 andin dotted lines in Figs. 3, 4, and 5) of the proper course in thehorizontal plane. V

Figure 3 at 35 shows the position of the two pointers when the plane ison the correct horizontal and vertical landing path of the beacons 36.31 (Fig. 4) shows the pointer indications when the airplane is above theproper vertical landing path and oif to the left of the runway, whilethe indication at 38 (Fig. 5) shows the plane too low and off to theright. To land a plane, the pilot merely holds the intersection of thetwo pointers over the central circle.

Driving unit ll, Figure 1, may be a 0-500 microameter and drivingunit [2a 200-0-200 microameter.

While the above is one form of my invention, the driving units II and I2may be of any con venient type and connected to any form of courseindicating receiving apparatus which may indicate vertical andhorizontal guidance.

What I claim is:

1. On an aircraft, a radio azimuth and zenith indicator comprising aface plate with a. hori zontal and a vertical line intersecting at rightangles, a pointer indicating degrees of azimuth moving in front of saidface plate in a plane parallel to it and coinciding with said verticalline when in midscale position, a second pointer indicating degrees ofzenith moving in front of said face plate in a plane parallel to it andcoinciding with said horizontal line when in midscale position andalways intersecting said first pointer, the point of intersectionindicating the azimuthal and zenithal position of said aircraft.

2. On an aircraft, a radio course indicator having a dial with an indexpoint indicating a predetermined course, and further having two movableintersecting pointers positioned to cooperatewith said index point t6show an on-course position of the aircraft, and signal responsive meansfor moving one of said pointers relatively to said index point in thesame direction on the dial as two movable intersecting pointers arrangedto intersect at all times, signal responsivemeans for operating saidpointers to cause the latter to intersect opposite said point'ofpredetermined course when said aircraft is on a predetermined course andto intersect at a point relative to said point of predetermined coursein the same direction as the deviation of said aircraft from saidpredetermined course.

. 4. In an electrical indicating instrument the.

combination of two pointers arranged to move in parallel planes and tointersect each other in all their indicating positions when operating,means for operating said pointers .to move relatively to each other, adial mounted for reading with the pointers and having an index mark atwhich said pointers may intersect in one of their operating positions,yielding means tending to normally instrument having two magneticfields, a revolubly mounted coil in one of said magnetic fields, apointer attached to said coil at right angles to the axis of rotation ofsaid coil, a second'revolubly mounted coil in the second of saidmagnetic fields with its axis of rotation parallel to said first axis ofrotation, a 'second pointer attached to said second coil, and extendingto move in a plane parallel to that of and to intersect at all timeswith said first pointer, a dial having a scale mounted for reading withintersection of said pointers and in a plane perpendicular to the axisof rotation of said coils, said dial having an index mark at its centerat which the pointers intersect in one of their positions, yieldingmeans attached to said first pointer and tendingto hold the latter atsaid center index mark, a second yieldvation area, two intersectingpointers mounted to traverse respectively the area before saidopening,one of said pointers being an end zero pointer and the other a centerzero pointer, electrically operated means on the indicator for operatingeach pointer, two sources of direct current potential, means connectingin opposition said .two sources to the operating means of the zerocenter pointer, third source of direct current potential for controllingthe zenithal indication, and means for connecting at will said end zeropointer operating means either to said third source or to said first andsecond sources in aiding polarity, wh by the end zero pointers will givezcnithalindications from the third source, or intensity indications fromsaid first and second sources with the center zero pointer givingazimuthal indications from said first and second sources.

7. An instrument for visibly indicating azi-- muthal and zenithalmovement of a mobile object with respect to a determined path ofmovement, said instrument comprising an area on which said visibleindications may be observed, two pointers arranged to intersect at alltimes before said area when operating,.one of the intersecting positionsdenoting. a determined path of movement of the 8. The combination withan indicating instrument having a pointer normally resting at one end ofits range of movement. of a second pointer normally standing at 'zerocenter of its range of movement, said pointers being arranged tointersect at all times and to intersect each other at right angles whenin their mid-scale positions with said .flrst pointer indicating asubstantially horizontal position and said second pointer indieating asubstantially vertical position, and signal 10 responsive means foroperating said pointers. FRANCIS W. DUNMORE.

